﻿using System;
using System.Collections.Generic;
using System.IO;
using System.Timers;


namespace SimplyService
{
    public class FTPFileSystemWatcher
    {
        private readonly string _path;
        public event FileSystemEventHandler FTPFileCreated;
        public event FileSystemEventHandler FTPFileDeleted;
        public event FileSystemEventHandler FTPFileChanged;

        private Dictionary<string, LastWriteTime> _createdFilesToCheck;
        private readonly object _lockObject = new object();
        private const int _milliSecondsSinceLastWrite = 5000;
        private const int _createdCheckTimerInterval = 2000;

        private readonly FileSystemWatcher _baseWatcher;

        public FTPFileSystemWatcher(string path, string Filter)
        {
            _path = path;
            _baseWatcher = new FileSystemWatcher(path, Filter);
            SetUpEventHandling();
        }

        public FTPFileSystemWatcher(string path)
        {
            _path = path;
            _baseWatcher = new FileSystemWatcher(path);
            SetUpEventHandling();
        }

        private void SetUpEventHandling()
        {
            _createdFilesToCheck = new Dictionary<string, LastWriteTime>();
            Timer copyTimer = new Timer(_createdCheckTimerInterval);
            copyTimer.Elapsed += copyTimer_Elapsed;
            copyTimer.Enabled = true;
            copyTimer.Start();
            _baseWatcher.EnableRaisingEvents = true;
            _baseWatcher.Created += _baseWatcher_Created;
            _baseWatcher.Deleted += _baseWatcher_Deleted;
            _baseWatcher.Changed += _baseWatcher_Changed;
        }

        void copyTimer_Elapsed(object sender, ElapsedEventArgs e)
        {
            lock (_lockObject)
            {
                Console.WriteLine("Checking : " + DateTime.Now);
                DateTime dateToCheck = DateTime.Now;
                List<string> toRemove = new List<string>();
                foreach (KeyValuePair<string, LastWriteTime> fileToCopy in _createdFilesToCheck)
                {
                    FileInfo fileToCheck = new FileInfo(_path + fileToCopy.Key);
                    TimeSpan difference = fileToCheck.LastWriteTime - fileToCopy.Value.Date;
                    fileToCopy.Value.Update(fileToCopy.Value.Date.AddMilliseconds(difference.TotalMilliseconds));
                    if (fileToCopy.Value.Date.AddMilliseconds(_milliSecondsSinceLastWrite) < dateToCheck)
                    {
                        FileSystemEventArgs args = new FileSystemEventArgs(WatcherChangeTypes.Created, _path, fileToCopy.Key);
                        toRemove.Add(fileToCopy.Key);
                        InvokeFTPFileCreated(args);
                    }
                }
                foreach (string removal in toRemove)
                {
                    _createdFilesToCheck.Remove(removal);
                }
            }
        }

        void _baseWatcher_Changed(object sender, FileSystemEventArgs e)
        {
            InvokeFTPFileChanged(e);
        }

        void _baseWatcher_Deleted(object sender, FileSystemEventArgs e)
        {
            InvokeFTPFileDeleted(e);
        }

        void _baseWatcher_Created(object sender, FileSystemEventArgs e)
        {
            if (!_createdFilesToCheck.ContainsKey(e.Name))
            {
                FileInfo fileToCopy = new FileInfo(e.FullPath);
                _createdFilesToCheck.Add(e.Name, new LastWriteTime(fileToCopy.LastWriteTime));
            }
        }

        private void InvokeFTPFileChanged(FileSystemEventArgs e)
        {
            FileSystemEventHandler Handler = FTPFileChanged;
            if (Handler != null)
            {
                Handler(this, e);
            }
        }

        private void InvokeFTPFileDeleted(FileSystemEventArgs e)
        {
            FileSystemEventHandler Handler = FTPFileDeleted;
            if (Handler != null)
            {
                Handler(this, e);
            }
        }

        private void InvokeFTPFileCreated(FileSystemEventArgs e)
        {
            FileSystemEventHandler Handler = FTPFileCreated;
            if (Handler != null)
            {
                Handler(this, e);
            }
        }
    }

    public class LastWriteTime
    {
        private DateTime _date;

        public DateTime Date
        {
            get { return _date; }
        }

        public LastWriteTime(DateTime date)
        {
            _date = date;
        }

        public void Update(DateTime dateTime)
        {
            _date = dateTime;
        }



    }
}
